Preheat oven to 425 degrees. Line two muffin sheets with 14 liners or spray with non-stick spray. Set aside.
In a small bowl, add the brown sugar, flour, and cinnamon to a small bowl and mix until combined. Add the melted butter and mix until crumbs form. Set aside.
In a large bowl, toss the flour, baking powder, baking soda, salt, cinnamon and pumpkin pie spice together until combined. Set aside. In a medium bowl, whisk the brown sugar and eggs together until combined. Whisk in the pumpkin, oil, milk, and vanilla. Pour the wet ingredients into the dry ingredients and stir until just combined. Do NOT overmix the batter.
In a medium bowl, beat the cream cheese with an electric handheld (or stand) mixer on medium-high speed until creamy. Add the egg yolk, vanilla extract, and sugar. Beat until combined.
Spoon 1 Tablespoon of pumpkin muffin batter into the muffin cups. Layer with about 1 spoonful of cheesecake filling, then another Tablespoon of muffin batter or however much batter is needed to fill the cups all the way to the top. Sprinkle each muffin evenly with crumb topping and gently press the topping down into the muffin so it stays in place.
Bake for 5 minutes at 425 degrees then, keeping the muffins in the oven, reduce heat to 350 degrees and continue baking for another 15-16 minutes. The total time these muffins should be in the oven is around 20-21 minutes. Allow the muffins to cool for 10 minutes in the muffin sheet, then transfer to a wire rack to cool until ready to eat. ENJOY!
Recipe by Crumbs and Chaos at http://www.crumbsandchaos.dreamhosters.com/2015/09/pumpkin-cheesecake-muffins/